* [PATCH] fs/squashfs: use do_div function for math
@ 2022-05-05 9:26 Sean Nyekjaer
2022-05-05 13:15 ` Tom Rini
0 siblings, 1 reply; 11+ messages in thread
From: Sean Nyekjaer @ 2022-05-05 9:26 UTC (permalink / raw)
To: u-boot; +Cc: Sean Nyekjaer, trini
From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
When compling for x86:
ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
---
fs/squashfs/sqfs.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
index 5d9c52af80..6405db4ff3 100644
--- a/fs/squashfs/sqfs.c
+++ b/fs/squashfs/sqfs.c
@@ -8,6 +8,7 @@
*/
#include <asm/unaligned.h>
+#include <div64.h>
#include <errno.h>
#include <fs.h>
#include <linux/types.h>
@@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
}
for (j = 0; j < datablk_count; j++) {
- start = data_offset / ctxt.cur_dev->blksz;
+ start = do_div(data_offset, ctxt.cur_dev->blksz);
table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
table_offset = data_offset - (start * ctxt.cur_dev->blksz);
n_blks = DIV_ROUND_UP(table_size + table_offset,
@@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
goto out;
}
- start = frag_entry.start / ctxt.cur_dev->blksz;
+ start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
table_size = SQFS_BLOCK_SIZE(frag_entry.size);
table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
--
2.35.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-05 9:26 [PATCH] fs/squashfs: use do_div function for math Sean Nyekjaer
@ 2022-05-05 13:15 ` Tom Rini
2022-05-09 13:08 ` Miquel Raynal
0 siblings, 1 reply; 11+ messages in thread
From: Tom Rini @ 2022-05-05 13:15 UTC (permalink / raw)
To: Sean Nyekjaer, Joao Marcos Costa, Thomas Petazzoni, Miquel Raynal
Cc: u-boot, Sean Nyekjaer
[-- Attachment #1: Type: text/plain, Size: 1757 bytes --]
On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
>
> When compling for x86:
> ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
> ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
>
> Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> ---
> fs/squashfs/sqfs.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> index 5d9c52af80..6405db4ff3 100644
> --- a/fs/squashfs/sqfs.c
> +++ b/fs/squashfs/sqfs.c
> @@ -8,6 +8,7 @@
> */
>
> #include <asm/unaligned.h>
> +#include <div64.h>
> #include <errno.h>
> #include <fs.h>
> #include <linux/types.h>
> @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> }
>
> for (j = 0; j < datablk_count; j++) {
> - start = data_offset / ctxt.cur_dev->blksz;
> + start = do_div(data_offset, ctxt.cur_dev->blksz);
> table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> table_offset = data_offset - (start * ctxt.cur_dev->blksz);
> n_blks = DIV_ROUND_UP(table_size + table_offset,
> @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> goto out;
> }
>
> - start = frag_entry.start / ctxt.cur_dev->blksz;
> + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
> n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
Adding maintainers...
--
Tom
[-- Attachment #2: signature.asc --]
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-05 13:15 ` Tom Rini
@ 2022-05-09 13:08 ` Miquel Raynal
2022-05-12 10:19 ` Pali Rohár
0 siblings, 1 reply; 11+ messages in thread
From: Miquel Raynal @ 2022-05-09 13:08 UTC (permalink / raw)
To: Tom Rini
Cc: Sean Nyekjaer, Joao Marcos Costa, Thomas Petazzoni, u-boot,
Sean Nyekjaer
Hello,
trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
> On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
>
> > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> >
> > When compling for x86:
> > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
> > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
> >
> > Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > ---
> > fs/squashfs/sqfs.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > index 5d9c52af80..6405db4ff3 100644
> > --- a/fs/squashfs/sqfs.c
> > +++ b/fs/squashfs/sqfs.c
> > @@ -8,6 +8,7 @@
> > */
> >
> > #include <asm/unaligned.h>
> > +#include <div64.h>
> > #include <errno.h>
> > #include <fs.h>
> > #include <linux/types.h>
> > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > }
> >
> > for (j = 0; j < datablk_count; j++) {
> > - start = data_offset / ctxt.cur_dev->blksz;
> > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > table_offset = data_offset - (start * ctxt.cur_dev->blksz);
> > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > goto out;
> > }
> >
> > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
> > n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
>
> Adding maintainers...
I guess that's a correct fix, so
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Thanks,
Miquèl
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-09 13:08 ` Miquel Raynal
@ 2022-05-12 10:19 ` Pali Rohár
2022-05-12 10:24 ` Pali Rohár
0 siblings, 1 reply; 11+ messages in thread
From: Pali Rohár @ 2022-05-12 10:19 UTC (permalink / raw)
To: Miquel Raynal
Cc: Tom Rini, Sean Nyekjaer, Joao Marcos Costa, Thomas Petazzoni,
u-boot, Sean Nyekjaer
On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
> Hello,
>
> trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
>
> > On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> >
> > > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > >
> > > When compling for x86:
> > > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
> > > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
> > >
> > > Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > ---
> > > fs/squashfs/sqfs.c | 5 +++--
> > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > index 5d9c52af80..6405db4ff3 100644
> > > --- a/fs/squashfs/sqfs.c
> > > +++ b/fs/squashfs/sqfs.c
> > > @@ -8,6 +8,7 @@
> > > */
> > >
> > > #include <asm/unaligned.h>
> > > +#include <div64.h>
> > > #include <errno.h>
> > > #include <fs.h>
> > > #include <linux/types.h>
> > > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > }
> > >
> > > for (j = 0; j < datablk_count; j++) {
> > > - start = data_offset / ctxt.cur_dev->blksz;
> > > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > > table_offset = data_offset - (start * ctxt.cur_dev->blksz);
> > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > goto out;
> > > }
> > >
> > > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > > table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
> > > n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
> >
> > Adding maintainers...
>
> I guess that's a correct fix, so
>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
>
> Thanks,
> Miquèl
Hello! do_div() macro modifies its first argument. It is correct?
Because previous code did not modify anything.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-12 10:19 ` Pali Rohár
@ 2022-05-12 10:24 ` Pali Rohár
2022-05-12 18:02 ` Sean Nyekjaer
0 siblings, 1 reply; 11+ messages in thread
From: Pali Rohár @ 2022-05-12 10:24 UTC (permalink / raw)
To: Miquel Raynal
Cc: Tom Rini, Sean Nyekjaer, Joao Marcos Costa, Thomas Petazzoni,
u-boot, Sean Nyekjaer
On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
> On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
> > Hello,
> >
> > trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
> >
> > > On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> > >
> > > > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > >
> > > > When compling for x86:
> > > > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > > > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
> > > > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
> > > >
> > > > Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > ---
> > > > fs/squashfs/sqfs.c | 5 +++--
> > > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > > index 5d9c52af80..6405db4ff3 100644
> > > > --- a/fs/squashfs/sqfs.c
> > > > +++ b/fs/squashfs/sqfs.c
> > > > @@ -8,6 +8,7 @@
> > > > */
> > > >
> > > > #include <asm/unaligned.h>
> > > > +#include <div64.h>
> > > > #include <errno.h>
> > > > #include <fs.h>
> > > > #include <linux/types.h>
> > > > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > }
> > > >
> > > > for (j = 0; j < datablk_count; j++) {
> > > > - start = data_offset / ctxt.cur_dev->blksz;
> > > > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > > > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > > > table_offset = data_offset - (start * ctxt.cur_dev->blksz);
> > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > > > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > goto out;
> > > > }
> > > >
> > > > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > > > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > > > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > > > table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
> > > > n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
> > >
> > > Adding maintainers...
> >
> > I guess that's a correct fix, so
> >
> > Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> >
> > Thanks,
> > Miquèl
>
> Hello! do_div() macro modifies its first argument. It is correct?
> Because previous code did not modify anything.
* The semantics of do_div() are:
*
* u32 do_div(u64 *n, u32 base)
* {
* u32 remainder = *n % base;
* *n = *n / base;
* return remainder;
* }
And this patch replaced:
start = data_offset / ctxt.cur_dev->blksz;
by:
start = do_div(data_offset, ctxt.cur_dev->blksz);
which expands to:
start = data_offset % ctxt.cur_dev->blksz;
data_offset = data_offset / ctxt.cur_dev->blksz;
Which is wrong as it calculates something totally different.
So this patch is incorrect.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-12 10:24 ` Pali Rohár
@ 2022-05-12 18:02 ` Sean Nyekjaer
2022-05-12 18:23 ` Tom Rini
` (2 more replies)
0 siblings, 3 replies; 11+ messages in thread
From: Sean Nyekjaer @ 2022-05-12 18:02 UTC (permalink / raw)
To: Pali Rohár
Cc: Miquel Raynal, Tom Rini, Joao Marcos Costa, Thomas Petazzoni,
u-boot, Sean Nyekjaer
On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
> On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
> > On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
> > > Hello,
> > >
> > > trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
> > >
> > > > On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> > > >
> > > > > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > >
> > > > > When compling for x86:
> > > > > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > > > > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
> > > > > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
> > > > >
> > > > > Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > ---
> > > > > fs/squashfs/sqfs.c | 5 +++--
> > > > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > > > >
> > > > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > > > index 5d9c52af80..6405db4ff3 100644
> > > > > --- a/fs/squashfs/sqfs.c
> > > > > +++ b/fs/squashfs/sqfs.c
> > > > > @@ -8,6 +8,7 @@
> > > > > */
> > > > >
> > > > > #include <asm/unaligned.h>
> > > > > +#include <div64.h>
> > > > > #include <errno.h>
> > > > > #include <fs.h>
> > > > > #include <linux/types.h>
> > > > > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > > }
> > > > >
> > > > > for (j = 0; j < datablk_count; j++) {
> > > > > - start = data_offset / ctxt.cur_dev->blksz;
> > > > > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > > > > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > > > > table_offset = data_offset - (start * ctxt.cur_dev->blksz);
> > > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > > > > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > > goto out;
> > > > > }
> > > > >
> > > > > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > > > > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > > > > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > > > > table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
> > > > > n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
> > > >
> > > > Adding maintainers...
> > >
> > > I guess that's a correct fix, so
> > >
> > > Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > >
> > > Thanks,
> > > Miquèl
> >
> > Hello! do_div() macro modifies its first argument. It is correct?
> > Because previous code did not modify anything.
>
> * The semantics of do_div() are:
> *
> * u32 do_div(u64 *n, u32 base)
> * {
> * u32 remainder = *n % base;
> * *n = *n / base;
> * return remainder;
> * }
>
> And this patch replaced:
>
> start = data_offset / ctxt.cur_dev->blksz;
>
> by:
>
> start = do_div(data_offset, ctxt.cur_dev->blksz);
>
> which expands to:
>
> start = data_offset % ctxt.cur_dev->blksz;
> data_offset = data_offset / ctxt.cur_dev->blksz;
>
> Which is wrong as it calculates something totally different.
>
> So this patch is incorrect.
Hi Pali,
Yes I agree, I got tricked by some wrong cache from Yocto :/
I have tried lldiv(), and that works on our x86 target.
Do you have an opinion on that?
Or do you have another idea to avoid the
"undefined reference to `__udivmoddi4'" error?
/Sean
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-12 18:02 ` Sean Nyekjaer
@ 2022-05-12 18:23 ` Tom Rini
2022-05-12 18:41 ` Pali Rohár
2022-05-12 18:52 ` Michael Nazzareno Trimarchi
2 siblings, 0 replies; 11+ messages in thread
From: Tom Rini @ 2022-05-12 18:23 UTC (permalink / raw)
To: Sean Nyekjaer
Cc: Pali Rohár, Miquel Raynal, Joao Marcos Costa,
Thomas Petazzoni, u-boot, Sean Nyekjaer
[-- Attachment #1: Type: text/plain, Size: 3812 bytes --]
On Thu, May 12, 2022 at 08:02:33PM +0200, Sean Nyekjaer wrote:
> On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
> > On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
> > > On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
> > > > Hello,
> > > >
> > > > trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
> > > >
> > > > > On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> > > > >
> > > > > > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > >
> > > > > > When compling for x86:
> > > > > > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > > > > > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
> > > > > > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
> > > > > >
> > > > > > Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > > ---
> > > > > > fs/squashfs/sqfs.c | 5 +++--
> > > > > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > > > > >
> > > > > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > > > > index 5d9c52af80..6405db4ff3 100644
> > > > > > --- a/fs/squashfs/sqfs.c
> > > > > > +++ b/fs/squashfs/sqfs.c
> > > > > > @@ -8,6 +8,7 @@
> > > > > > */
> > > > > >
> > > > > > #include <asm/unaligned.h>
> > > > > > +#include <div64.h>
> > > > > > #include <errno.h>
> > > > > > #include <fs.h>
> > > > > > #include <linux/types.h>
> > > > > > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > > > }
> > > > > >
> > > > > > for (j = 0; j < datablk_count; j++) {
> > > > > > - start = data_offset / ctxt.cur_dev->blksz;
> > > > > > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > > > > > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > > > > > table_offset = data_offset - (start * ctxt.cur_dev->blksz);
> > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > > > > > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > > > goto out;
> > > > > > }
> > > > > >
> > > > > > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > > > > > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > > > > > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > > > > > table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
> > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
> > > > >
> > > > > Adding maintainers...
> > > >
> > > > I guess that's a correct fix, so
> > > >
> > > > Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > > >
> > > > Thanks,
> > > > Miquèl
> > >
> > > Hello! do_div() macro modifies its first argument. It is correct?
> > > Because previous code did not modify anything.
> >
> > * The semantics of do_div() are:
> > *
> > * u32 do_div(u64 *n, u32 base)
> > * {
> > * u32 remainder = *n % base;
> > * *n = *n / base;
> > * return remainder;
> > * }
> >
> > And this patch replaced:
> >
> > start = data_offset / ctxt.cur_dev->blksz;
> >
> > by:
> >
> > start = do_div(data_offset, ctxt.cur_dev->blksz);
> >
> > which expands to:
> >
> > start = data_offset % ctxt.cur_dev->blksz;
> > data_offset = data_offset / ctxt.cur_dev->blksz;
> >
> > Which is wrong as it calculates something totally different.
> >
> > So this patch is incorrect.
>
> Hi Pali,
>
> Yes I agree, I got tricked by some wrong cache from Yocto :/
> I have tried lldiv(), and that works on our x86 target.
>
> Do you have an opinion on that?
> Or do you have another idea to avoid the
> "undefined reference to `__udivmoddi4'" error?
Please correct things to use lldiv(), thanks.
--
Tom
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 659 bytes --]
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-12 18:02 ` Sean Nyekjaer
2022-05-12 18:23 ` Tom Rini
@ 2022-05-12 18:41 ` Pali Rohár
2022-05-12 18:47 ` Sean Nyekjaer
2022-05-12 18:52 ` Michael Nazzareno Trimarchi
2 siblings, 1 reply; 11+ messages in thread
From: Pali Rohár @ 2022-05-12 18:41 UTC (permalink / raw)
To: Sean Nyekjaer
Cc: Miquel Raynal, Tom Rini, Joao Marcos Costa, Thomas Petazzoni,
u-boot, Sean Nyekjaer
On Thursday 12 May 2022 20:02:33 Sean Nyekjaer wrote:
> On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
> > On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
> > > On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
> > > > Hello,
> > > >
> > > > trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
> > > >
> > > > > On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> > > > >
> > > > > > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > >
> > > > > > When compling for x86:
> > > > > > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > > > > > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
> > > > > > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
> > > > > >
> > > > > > Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > > ---
> > > > > > fs/squashfs/sqfs.c | 5 +++--
> > > > > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > > > > >
> > > > > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > > > > index 5d9c52af80..6405db4ff3 100644
> > > > > > --- a/fs/squashfs/sqfs.c
> > > > > > +++ b/fs/squashfs/sqfs.c
> > > > > > @@ -8,6 +8,7 @@
> > > > > > */
> > > > > >
> > > > > > #include <asm/unaligned.h>
> > > > > > +#include <div64.h>
> > > > > > #include <errno.h>
> > > > > > #include <fs.h>
> > > > > > #include <linux/types.h>
> > > > > > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > > > }
> > > > > >
> > > > > > for (j = 0; j < datablk_count; j++) {
> > > > > > - start = data_offset / ctxt.cur_dev->blksz;
> > > > > > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > > > > > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > > > > > table_offset = data_offset - (start * ctxt.cur_dev->blksz);
> > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > > > > > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > > > goto out;
> > > > > > }
> > > > > >
> > > > > > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > > > > > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > > > > > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > > > > > table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
> > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
> > > > >
> > > > > Adding maintainers...
> > > >
> > > > I guess that's a correct fix, so
> > > >
> > > > Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > > >
> > > > Thanks,
> > > > Miquèl
> > >
> > > Hello! do_div() macro modifies its first argument. It is correct?
> > > Because previous code did not modify anything.
> >
> > * The semantics of do_div() are:
> > *
> > * u32 do_div(u64 *n, u32 base)
> > * {
> > * u32 remainder = *n % base;
> > * *n = *n / base;
> > * return remainder;
> > * }
> >
> > And this patch replaced:
> >
> > start = data_offset / ctxt.cur_dev->blksz;
> >
> > by:
> >
> > start = do_div(data_offset, ctxt.cur_dev->blksz);
> >
> > which expands to:
> >
> > start = data_offset % ctxt.cur_dev->blksz;
> > data_offset = data_offset / ctxt.cur_dev->blksz;
> >
> > Which is wrong as it calculates something totally different.
> >
> > So this patch is incorrect.
>
> Hi Pali,
>
> Yes I agree, I got tricked by some wrong cache from Yocto :/
> I have tried lldiv(), and that works on our x86 target.
>
> Do you have an opinion on that?
> Or do you have another idea to avoid the
> "undefined reference to `__udivmoddi4'" error?
>
> /Sean
Hello! You really should not use C division operator for 64-bit integers
as gcc still is not able to generate assembler code for such division
on many 32-bit platforms.
You should use some function or macro from linux/math64.h or div64.h
header file. For every combination of types, pairs and required
operation there is specific function/macro (e.g. u64/u32, u64%u32,
u64/u64, etc...).
I think that lldiv() is the correct call here. This function expects u64
as dividend, u32 as divisor and returns u64 result.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-12 18:41 ` Pali Rohár
@ 2022-05-12 18:47 ` Sean Nyekjaer
0 siblings, 0 replies; 11+ messages in thread
From: Sean Nyekjaer @ 2022-05-12 18:47 UTC (permalink / raw)
To: Pali Rohár
Cc: Miquel Raynal, Tom Rini, Joao Marcos Costa, Thomas Petazzoni,
u-boot, Sean Nyekjaer
On Thu, May 12, 2022 at 08:41:15PM +0200, Pali Rohár wrote:
> On Thursday 12 May 2022 20:02:33 Sean Nyekjaer wrote:
> > On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
> > > On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
> > > > On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
> > > > > Hello,
> > > > >
> > > > > trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
> > > > >
> > > > > > On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> > > > > >
> > > > > > > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > > >
> > > > > > > When compling for x86:
> > > > > > > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > > > > > > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to `__udivmoddi4'
> > > > > > > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to `__udivmoddi4'
> > > > > > >
> > > > > > > Signed-off-by: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > > > ---
> > > > > > > fs/squashfs/sqfs.c | 5 +++--
> > > > > > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > > > > > >
> > > > > > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > > > > > index 5d9c52af80..6405db4ff3 100644
> > > > > > > --- a/fs/squashfs/sqfs.c
> > > > > > > +++ b/fs/squashfs/sqfs.c
> > > > > > > @@ -8,6 +8,7 @@
> > > > > > > */
> > > > > > >
> > > > > > > #include <asm/unaligned.h>
> > > > > > > +#include <div64.h>
> > > > > > > #include <errno.h>
> > > > > > > #include <fs.h>
> > > > > > > #include <linux/types.h>
> > > > > > > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > > > > }
> > > > > > >
> > > > > > > for (j = 0; j < datablk_count; j++) {
> > > > > > > - start = data_offset / ctxt.cur_dev->blksz;
> > > > > > > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > > > > > > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > > > > > > table_offset = data_offset - (start * ctxt.cur_dev->blksz);
> > > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > > > > > > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len,
> > > > > > > goto out;
> > > > > > > }
> > > > > > >
> > > > > > > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > > > > > > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > > > > > > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > > > > > > table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz);
> > > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz);
> > > > > >
> > > > > > Adding maintainers...
> > > > >
> > > > > I guess that's a correct fix, so
> > > > >
> > > > > Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > > > >
> > > > > Thanks,
> > > > > Miquèl
> > > >
> > > > Hello! do_div() macro modifies its first argument. It is correct?
> > > > Because previous code did not modify anything.
> > >
> > > * The semantics of do_div() are:
> > > *
> > > * u32 do_div(u64 *n, u32 base)
> > > * {
> > > * u32 remainder = *n % base;
> > > * *n = *n / base;
> > > * return remainder;
> > > * }
> > >
> > > And this patch replaced:
> > >
> > > start = data_offset / ctxt.cur_dev->blksz;
> > >
> > > by:
> > >
> > > start = do_div(data_offset, ctxt.cur_dev->blksz);
> > >
> > > which expands to:
> > >
> > > start = data_offset % ctxt.cur_dev->blksz;
> > > data_offset = data_offset / ctxt.cur_dev->blksz;
> > >
> > > Which is wrong as it calculates something totally different.
> > >
> > > So this patch is incorrect.
> >
> > Hi Pali,
> >
> > Yes I agree, I got tricked by some wrong cache from Yocto :/
> > I have tried lldiv(), and that works on our x86 target.
> >
> > Do you have an opinion on that?
> > Or do you have another idea to avoid the
> > "undefined reference to `__udivmoddi4'" error?
> >
> > /Sean
>
> Hello! You really should not use C division operator for 64-bit integers
> as gcc still is not able to generate assembler code for such division
> on many 32-bit platforms.
>
> You should use some function or macro from linux/math64.h or div64.h
> header file. For every combination of types, pairs and required
> operation there is specific function/macro (e.g. u64/u32, u64%u32,
> u64/u64, etc...).
>
> I think that lldiv() is the correct call here. This function expects u64
> as dividend, u32 as divisor and returns u64 result.
Thank you for the explanation :)
Updated patch should be on the list.
/Sean
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-12 18:02 ` Sean Nyekjaer
2022-05-12 18:23 ` Tom Rini
2022-05-12 18:41 ` Pali Rohár
@ 2022-05-12 18:52 ` Michael Nazzareno Trimarchi
2022-05-12 18:55 ` Pali Rohár
2 siblings, 1 reply; 11+ messages in thread
From: Michael Nazzareno Trimarchi @ 2022-05-12 18:52 UTC (permalink / raw)
To: Sean Nyekjaer
Cc: Pali Rohár, Miquel Raynal, Tom Rini, Joao Marcos Costa,
Thomas Petazzoni, U-Boot-Denx, Sean Nyekjaer
Hi
Il gio 12 mag 2022, 20:02 Sean Nyekjaer <sean@geanix.com> ha scritto:
> On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
> > On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
> > > On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
> > > > Hello,
> > > >
> > > > trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
> > > >
> > > > > On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> > > > >
> > > > > > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > >
> > > > > > When compling for x86:
> > > > > > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > > > > > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to
> `__udivmoddi4'
> > > > > > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to
> `__udivmoddi4'
> > > > > >
> > > > > > Signed-off-by: Sean Nyekjaer <
> sean.nyekjaer.ext@siemensgamesa.com>
> > > > > > ---
> > > > > > fs/squashfs/sqfs.c | 5 +++--
> > > > > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > > > > >
> > > > > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > > > > index 5d9c52af80..6405db4ff3 100644
> > > > > > --- a/fs/squashfs/sqfs.c
> > > > > > +++ b/fs/squashfs/sqfs.c
> > > > > > @@ -8,6 +8,7 @@
> > > > > > */
> > > > > >
> > > > > > #include <asm/unaligned.h>
> > > > > > +#include <div64.h>
> > > > > > #include <errno.h>
> > > > > > #include <fs.h>
> > > > > > #include <linux/types.h>
> > > > > > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void
> *buf, loff_t offset, loff_t len,
> > > > > > }
> > > > > >
> > > > > > for (j = 0; j < datablk_count; j++) {
> > > > > > - start = data_offset / ctxt.cur_dev->blksz;
> > > > > > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > > > > > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > > > > > table_offset = data_offset - (start *
> ctxt.cur_dev->blksz);
> > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > > > > > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void
> *buf, loff_t offset, loff_t len,
> > > > > > goto out;
> > > > > > }
> > > > > >
> > > > > > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > > > > > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > > > > > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > > > > > table_offset = frag_entry.start - (start *
> ctxt.cur_dev->blksz);
> > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> ctxt.cur_dev->blksz);
> > > > >
> > > > > Adding maintainers...
> > > >
> > > > I guess that's a correct fix, so
> > > >
> > > > Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > > >
> > > > Thanks,
> > > > Miquèl
> > >
> > > Hello! do_div() macro modifies its first argument. It is correct?
> > > Because previous code did not modify anything.
> >
> > * The semantics of do_div() are:
> > *
> > * u32 do_div(u64 *n, u32 base)
> > * {
> > * u32 remainder = *n % base;
> > * *n = *n / base;
> > * return remainder;
> > * }
> >
> > And this patch replaced:
> >
> > start = data_offset / ctxt.cur_dev->blksz;
> >
> > by:
> >
> > start = do_div(data_offset, ctxt.cur_dev->blksz);
> >
> > which expands to:
> >
> > start = data_offset % ctxt.cur_dev->blksz;
> > data_offset = data_offset / ctxt.cur_dev->blksz;
> >
> > Which is wrong as it calculates something totally different.
> >
> > So this patch is incorrect.
>
> Hi Pali,
>
> Yes I agree, I got tricked by some wrong cache from Yocto :/
> I have tried lldiv(), and that works on our x86 target.
>
start = data_offset;
do_div(start, ctxt.cur_dev->blksz);
Something like this?
Michael
> Do you have an opinion on that?
> Or do you have another idea to avoid the
> "undefined reference to `__udivmoddi4'" error?
>
> /Sean
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] fs/squashfs: use do_div function for math
2022-05-12 18:52 ` Michael Nazzareno Trimarchi
@ 2022-05-12 18:55 ` Pali Rohár
0 siblings, 0 replies; 11+ messages in thread
From: Pali Rohár @ 2022-05-12 18:55 UTC (permalink / raw)
To: Michael Nazzareno Trimarchi
Cc: Sean Nyekjaer, Miquel Raynal, Tom Rini, Joao Marcos Costa,
Thomas Petazzoni, U-Boot-Denx, Sean Nyekjaer
On Thursday 12 May 2022 20:52:30 Michael Nazzareno Trimarchi wrote:
> Hi
>
> Il gio 12 mag 2022, 20:02 Sean Nyekjaer <sean@geanix.com> ha scritto:
>
> > On Thu, May 12, 2022 at 12:24:01PM +0200, Pali Rohár wrote:
> > > On Thursday 12 May 2022 12:19:01 Pali Rohár wrote:
> > > > On Monday 09 May 2022 15:08:15 Miquel Raynal wrote:
> > > > > Hello,
> > > > >
> > > > > trini@konsulko.com wrote on Thu, 5 May 2022 09:15:00 -0400:
> > > > >
> > > > > > On Thu, May 05, 2022 at 11:26:37AM +0200, Sean Nyekjaer wrote:
> > > > > >
> > > > > > > From: Sean Nyekjaer <sean.nyekjaer.ext@siemensgamesa.com>
> > > > > > >
> > > > > > > When compling for x86:
> > > > > > > ld.bfd: fs/squashfs/sqfs.o: in function `sqfs_read':
> > > > > > > u-boot/fs/squashfs/sqfs.c:1443: undefined reference to
> > `__udivmoddi4'
> > > > > > > ld.bfd: u-boot/fs/squashfs/sqfs.c:1521: undefined reference to
> > `__udivmoddi4'
> > > > > > >
> > > > > > > Signed-off-by: Sean Nyekjaer <
> > sean.nyekjaer.ext@siemensgamesa.com>
> > > > > > > ---
> > > > > > > fs/squashfs/sqfs.c | 5 +++--
> > > > > > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > > > > > >
> > > > > > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > > > > > index 5d9c52af80..6405db4ff3 100644
> > > > > > > --- a/fs/squashfs/sqfs.c
> > > > > > > +++ b/fs/squashfs/sqfs.c
> > > > > > > @@ -8,6 +8,7 @@
> > > > > > > */
> > > > > > >
> > > > > > > #include <asm/unaligned.h>
> > > > > > > +#include <div64.h>
> > > > > > > #include <errno.h>
> > > > > > > #include <fs.h>
> > > > > > > #include <linux/types.h>
> > > > > > > @@ -1440,7 +1441,7 @@ int sqfs_read(const char *filename, void
> > *buf, loff_t offset, loff_t len,
> > > > > > > }
> > > > > > >
> > > > > > > for (j = 0; j < datablk_count; j++) {
> > > > > > > - start = data_offset / ctxt.cur_dev->blksz;
> > > > > > > + start = do_div(data_offset, ctxt.cur_dev->blksz);
> > > > > > > table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]);
> > > > > > > table_offset = data_offset - (start *
> > ctxt.cur_dev->blksz);
> > > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > > > > > > @@ -1516,7 +1517,7 @@ int sqfs_read(const char *filename, void
> > *buf, loff_t offset, loff_t len,
> > > > > > > goto out;
> > > > > > > }
> > > > > > >
> > > > > > > - start = frag_entry.start / ctxt.cur_dev->blksz;
> > > > > > > + start = do_div(frag_entry.start, ctxt.cur_dev->blksz);
> > > > > > > table_size = SQFS_BLOCK_SIZE(frag_entry.size);
> > > > > > > table_offset = frag_entry.start - (start *
> > ctxt.cur_dev->blksz);
> > > > > > > n_blks = DIV_ROUND_UP(table_size + table_offset,
> > ctxt.cur_dev->blksz);
> > > > > >
> > > > > > Adding maintainers...
> > > > >
> > > > > I guess that's a correct fix, so
> > > > >
> > > > > Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > > > >
> > > > > Thanks,
> > > > > Miquèl
> > > >
> > > > Hello! do_div() macro modifies its first argument. It is correct?
> > > > Because previous code did not modify anything.
> > >
> > > * The semantics of do_div() are:
> > > *
> > > * u32 do_div(u64 *n, u32 base)
> > > * {
> > > * u32 remainder = *n % base;
> > > * *n = *n / base;
> > > * return remainder;
> > > * }
> > >
> > > And this patch replaced:
> > >
> > > start = data_offset / ctxt.cur_dev->blksz;
> > >
> > > by:
> > >
> > > start = do_div(data_offset, ctxt.cur_dev->blksz);
> > >
> > > which expands to:
> > >
> > > start = data_offset % ctxt.cur_dev->blksz;
> > > data_offset = data_offset / ctxt.cur_dev->blksz;
> > >
> > > Which is wrong as it calculates something totally different.
> > >
> > > So this patch is incorrect.
> >
> > Hi Pali,
> >
> > Yes I agree, I got tricked by some wrong cache from Yocto :/
> > I have tried lldiv(), and that works on our x86 target.
> >
>
> start = data_offset;
> do_div(start, ctxt.cur_dev->blksz);
>
> Something like this?
This is another option and seems that should be OK too.
> Michael
>
>
> > Do you have an opinion on that?
> > Or do you have another idea to avoid the
> > "undefined reference to `__udivmoddi4'" error?
> >
> > /Sean
> >
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2022-05-12 18:55 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-05 9:26 [PATCH] fs/squashfs: use do_div function for math Sean Nyekjaer
2022-05-05 13:15 ` Tom Rini
2022-05-09 13:08 ` Miquel Raynal
2022-05-12 10:19 ` Pali Rohár
2022-05-12 10:24 ` Pali Rohár
2022-05-12 18:02 ` Sean Nyekjaer
2022-05-12 18:23 ` Tom Rini
2022-05-12 18:41 ` Pali Rohár
2022-05-12 18:47 ` Sean Nyekjaer
2022-05-12 18:52 ` Michael Nazzareno Trimarchi
2022-05-12 18:55 ` Pali Rohár
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